The efficacy of intensive, intermittent immunosuppressive drug therapy will be evaluated in patients with active lupus glomerulonephritis over a 30 month study period. Patients with renal biopsy documented active glomerulonephritis with or without renal functional deterioration will be treated with low dose corticosteroids and randomized to receive (a) intravenous methylprednisolone (1.0 gm/m2 monthly for 6 months or (b) intravenous cyclophosphamide 1.0 gm/m2 monthly for 6 months or (c) intravenous cyclophosphamide 1.0 gm/m2 monthly for 6 months and then every 3 months for the remaining 24 months of the study. During the final 24 months of the study, all patients will receive low dose prednisone. Active disease, as manifested by renal functional deterioration, increased proteinuria or worsened urinary sediment, will be treated by increased doses of prednisone. Comparison will be made of the number of favorable outcomes of renal function and glomerular pathology and drug related toxicities achieved by each treatment group at the end of the 6th and 30th study months.